A gas lock in the region of a filler outlet helps avoid dripping of the filling element after the filling process. Typical gas locks have bores or filler flow channels formed in the filling element or in an insert. For convenience in exposition, both bores and filler flow channels will be referred to as filler flow channels.
The filler flow channels extend parallel to a vertical or substantially vertical filling element axis and are open at both ends. The lower open ends of the filler flow channels form dispensing openings. During the filling process, filler flows from the dispensing openings in a free filling-jet towards a container to be filled.
The upper open ends or inlets of the filler flow channels cooperate with a flat, plunger-like valve body of a liquid valve. To end the filling process, this liquid valve is closed. This involves placing the valve body over all of the inlets, thus closing them off. Filler remaining in the filler flow channels after the closing operation is retained therein by virtue of a “pipette effect.” This prevents the filling element from dripping.
A disadvantage of such gas locks is that they are not suitable for a lumpy filler that contains hard constituents. This is because the hard constituents accumulate between the inlets of the filler flow channels in the inflow region of the gas lock and form bridges. As filling continues, networks of hard filler constituents or fibers form over or in the inlets. Ultimately, these will block the inlets. This is a particular problem in the case of fruit juices, which have fibrous constituents having lengths of up to 20 mm. These constituent fibers can, on their own, clog bores or filler flow channels having a diameter of 10 mm.
A known way to avoid this problem is to use filling elements that form a free filling-jet using a single filler flow channel of large cross-section, This filler flow channel is disposed downstream of the liquid valve in the direction of flow of the filler. The diameter of the flow channel is at most 7 mm-9 mm. The liquid valve, which controls the flow of filler and/or the quantity of filler to be introduced into the container, and which consists essentially of a valve body having a valve surface and a valve seat cooperating with the valve surface, is provided upstream of an inlet of the single filler flow channel, as seen in the direction of flow of the filler.
A disadvantage of the foregoing arrangement is that only a relatively low filling rate can be achieved. With such a filling element, it is not possible to increase the filling rate by arranging a plurality of parallel filler flow channels of large diameter. This is because when such an arrangement is used, closing the liquid valve can no longer prevent emptying of the filler flow channels, and thus, an undesirable dripping of the filling element. This is because once the liquid valve is closed, the filler flow channels are connected to each other in the region of their inlets, and thus mutually vent each other. The resulting interconnected filler flow channels form a communicating pipe system. As a result, even extremely small differences in the quantities of filler remaining in the individual filler flow channels lead to a movement of the filler within this system, loss of the gas lock function, and emptying of the filler flow channels.